If you didn't transmit your return to the IRS, you can just bring your information somewhere else and file through them. Just don't file the return you created in TurboTax.
However, if you did file, you can't retrieve your return. If it gets rejected by the IRS, you can go to your preparer and just make sure that you don't resubmit.
If it was accepted by the IRS, you will have to amend your tax return. Your preparer should be able to help you do this.